JavaScript原生实现列表分页导航栏逻辑

分页函数源码解析

//总页数，当前页数，跳转地址，第一页和最后一页之间显示的页码数量
function pageBar(tp,cp,url,pn){
    var str = ‘<ul class=”page”>';
    if(tp>1 && cp>1){
      var prev = cp-1;
      str += ‘<li><a class=”prev” title=”上一页” href=”javascript:goPage(‘+prev+‘,\”+url+‘\');”><span>上一页</span></a></li> ‘;
    }else{
      str += ‘<li><a class=”prev” title=”上一页” href=”javascript:void(0);”><span>上一页</span></a></li> ‘;
    }
    if(tp>1){
      //第一页
      if(cp==1){
        str +=‘<li class=”current”><a href=”javascript:goPage(1,\”+url+‘\');”><span>1</span></a></li> ‘;
      }else{
        str +=‘<li><a href=”javascript:goPage(1,\”+url+‘\');”><span>1</span></a></li> ‘;
      }

      if(tp>2){
        var pnh = Math.floor(pn/2);

        //循环开始页码
        var s = cp-pnh;
        if(s<=1){
          s = 2;
        }

        //循环结束页码
        var e = cp+pnh;
        if(e>=tp){
          e = tp-1;
        }

        if(s<=(1+pnh)){
          if(tp>(pn+2)){
            e = s+(pn-1);
            if(e>=tp){
              e = tp-1;
            }
          }else{
            s = 2;
          }
        }

        if(e>=(tp-pnh)){
          if(tp>(pn+2)){
            s = e-(pn-1);
            if(s<=1){
              s = 2;
            }
          }else{
            e = tp-1;
          }
        }

        if(e<s){
          e = s;
        }

        //第一页后的多页跳转
        if(s>2){
          var sp = cp-pn;
          if(sp<1){
            sp=1;
          }
          str += ‘<li><a name=”break” href=”javascript:goPage(‘+sp+‘,\”+url+‘\');”><span>…</span></a></li> ‘;
        }

        for(var i=s;i<=e;i++){
          if(i==cp){
            str += ‘<li class=”current”><a href=”javascript:goPage(‘+i+‘,\”+url+‘\');”><span>'+i+‘</span></a></li> ‘;
          }else{
            str += ‘<li><a href=”javascript:goPage(‘+i+‘,\”+url+‘\');”><span>'+i+‘</span></a></li> ‘;
          }
        }

        //最后一页前的多页跳转
        if(e < (tp-1)){
          var ep = cp+pn;
          if(ep>tp){
            ep=tp;
          }
          str += ‘<li><a name=”break” href=”javascript:goPage(‘+ep+‘,\”+url+‘\');”><span>…</span></a></li> ‘;
        }
      }

      //最后一页
      if(cp==tp){
        str +=‘<li class=”current”><a href=”javascript:goPage(‘+tp+‘,\”+url+‘\');”><span>'+tp+‘</span></a></li> ‘;
      }else{
        str +=‘<li><a href=”javascript:goPage(‘+tp+‘,\”+url+‘\');”><span>'+tp+‘</span></a></li> ‘;
      }

    }else{
      str +=‘ <li class=”current”><a href=”javascript:void(0);”><span>1</span></a></li> ‘;
    }

    if(tp>1 && cp<tp){
      var next = cp+1;
      str += ‘<li><a class=”next” title=”下一页” href=”javascript:goPage(‘+next+‘,\”+url+‘\');”><span>下一页</span></a></li>';
    }else{
      str += ‘<li><a class=”next” title=”下一页” href=”javascript:void(0);”><span>下一页</span></a></li>';
    }
    str += ‘</ul>';
    return str;
  }

  //跳转页码，跳转地址
  function goPage(cp,url){
    window.location.href = url+cp;
  }